Spring suspensions for vehicles



July 26, 1955 N. S. FOCHT SPRING SUSPENSIONS FOR VEHICLES Filed Sept.19, 1951 R m a m h w c m 1 R w w s .z b 59 "w j u N B ATTORNEY SPRINGSUSPENSIONS FGR VEHICLES Nevin S. Focllt, Garden City, N. Y.

Application September 19, 1951, Serial No. 247,255

2 Claims. (Cl. 267-45) This invention relates to spring suspensions forvehicles and is a continuation-in-part of my application Serial No.166,485 filed June 6, 1950, now abandoned.

An object of the present invention is to provide a spring suspensionincluding main or soft and auxiliary or heavy leaf springs arranged invertical alignment and connected medially to the vehicle axle by shacklemeans permitting the axle to tilt vertically relative to the chassis ina plane including the longitudinal axis of the axle without imposingtorque upon the auxiliary spring. In that connection, it is proposed tomake the main spring relatively soft as compared with the upper helperspring so that the softer main spring functions alone under lightvehicle loads and is only assisted by the stiffer auxiliary or helperspring under heavier loads or under large dynamic forces such as areproduced by large road bumps or by braking or by the centrifugal forceacting on the vehicle chassis in turning corners.

With the above, and other objects in view, which will more readilyappear as the nature of the invention is better understood, the sameconsists in the combination and arrangement of parts hereinafter morefully described and illustrated in the accompanying drawings, in which:

Figure l is a partial side elevation of a vehicle chassis illustratingthe application of the invention.

Figure 2 is an enlarged side elevation of the improved spring andshackle arrangement.

Figure 3 is a vertical section view taken on the line 3-3 of Figure 2.

Figure 4 is a detail view showing the shock absorber connecting thechassis with the lower relatively soft main spring.

Similar reference characters designate corresponding parts throughoutthe several figures of the drawings.

In the usual truck rear spring employing a helper spring, the mainspring is stiff enough to carry the wide variation in loading on therear wheels. Hence, under light loads the spring will not flex and thevehicle and driver are subjected to a rough ride. Only under heavy loadsdoes the vehicle ride smoothly.

According to the present invention, the springs are reversed. That is tosay, the main spring is of fewer leaves and hence soft. The helperspring comprises more leaves and hence is relatively stiff to carry thegreater and heavier loads.

The softer main spring is made usable by the combination about to beshown and described because the softer unstable main spring isstabilized due to the unique shackle arrangement plus stabilizingcontrols.

As shown in the drawings, A designates the vehicle chassis or runninggear which carries the vehicle body and B designates generally thespring suspension device of the present invention. It will, of course,be understood that the spring suspension device may be applied to any orall ,pairs of springs of a vehicle.

The spring device B comprises a main or soft spring of the leaf type anda relatively stiff superimposed auxiliary or helper spring 16, also ofthe leaf type. The

Patented July 26, 1955 ice - main spring 15 is. constantly effective toyieldably support the running gear or chassis A and rests on the axle1'2 to-which it is connected by suitable clips 18, the said clips inturn having means for receiving the shackle plates 19 connecting withthe spring clip 20 of the auxiliary spring 16.

The main spring 15 has one end connected to the support 21 by a fixedpin 15a while its other end is connected to the link suspension means22. The stiff spring 16 is anchored as at 16a to the member 21 while itsopposite end 16b is relatively free and adapted to cooperate with ashock absorber C of Figure l or sway control means C of Figure 2.

The spring 16 is connected to the chassis A so that it cannot movelongitudinally relative thereto. Moreover, since the shackle plates 19are connected to the clips 18 and 20 by pins which, as shown, extendlongitudinally relative to the vehicle, it is apparent that the spring16 cannot move longitudinally relative to the axle 17. Said spring 16,therefore, acts as a radius rod to hold the axle 17 againstsubstantially any movement other than vertical movement, relative to thechassis and thus relieves the spring 15 of certain loads which mightotherwise be imposed thereon. However, it is further apparent that theshackle connection between the axle 17 and the spring 16 is such as topermit free vertical tilting movements of the axle 17 relative to thechassis A in a plane including the longitudinal axis of the axle.Therefore, such tilting movements of the axle do not impose torque uponthe spring 16.

Figures 1 and 2 of the drawings illustrate the manner in which the stiifspring 16 cooperates with the related body stabilizing control device Cor C. When the chassis A is only lightly loaded only the main spring 15is effective to support the loaded running gear but upon predeterminedloading of the running gear the auxiliary spring 16 is renderedeffective to assist said main spring in supporting the loaded runninggear or chassis, and to also operate means for reducing shock and sidesway on the body.

As illustrated in Figure 4, it may be desirable to have a directlyconnected shock absorber between the axle and chassis. This shockabsorber 23 in Figure 4 provides a special control characteristic to acton low frequency roll or pitch so as to add stability to the soft mainspring under light vehicle loads when the auxiliary spring is notacting.

From the foregoing, it will be seen that the shackle arrangement 19connecting the springs 15 and 16 provides an effective radius rod toprevent braking or driving torque overstressing the lower main springwhich might otherwise cause it to fail.

I claim:

1. In a vehicle including a chassis and an axle, a leaf spring connectedat its ends to said chassis and rigidly connected intermediate its endsto said axle, an auxiliary leaf spring overlying and spaced above saidfirst mentioned leaf spring, a connection between one end of saidauxiliary leaf spring and said chassis at a point fixed with respect tosaid chassis, a connection between said axle and said auxiliary leafspring, and means rendering said auxiliary leaf spring ineffective toresist loads of predetermined weight and effective to resist loads inexcess of said predetermined weight imposed on said chassis, theconnection between said auxiliary leaf spring and said axle being rigidlongitudinally with respect to the vehicle so that said auxiliary leafspring acts as a radius rod to limit longitudinal movement of said axlerelative to said chassis, the connection between said auxiliary leafspring and said axle additionally being flexible transversely withrespect to the vehicle so that the axle may tilt vertically relative tothe chassis in a plane including the longitudinal axis References Citedin the file of this patent UNITED STATES PATENTS Neff May 10, 1921 LeMoon Oct. 4,- 1932 Ufielrnan May 15, 1934 Marshall Apr. 24, 1951 FOREIGNPATENTS Great Britain Mar. 5, 1935

